add "Paste JSON as Code" extension

[Mef45]

• I have read the note above about PRs contributing or fixing extensions
• I have tried reaching out to the extension maintainers about publishing this extension to Open VSX (if not, please create an issue in the extension's repo using this template).
• This extension has an OSI-approved OSS license (we don't accept proprietary extensions in this repository)

Description

This PR adds the Paste JSON as Code extension to the Open VSX repo.

The request to publish this extension on Open VSX was submitted back in 2021 and has been ignored ever since, so it seems like the extension authors aren't interested in adding their extension there themselves. This PR is meant to help them with that.